For stretches -- depends what hurts worst! With squats, I'm guessing thighs and buttocks, but DOMS has an amazing knack for turning up where you really wouldn't expect it.

Experiment (but gently *g*). Exrx.net has lots of simple stretches; you could try these for starters:

http://www.exrx.net/Stretches/GluteusMaximus/Lying.html
http://www.exrx.net/Stretches/Quadriceps/ProneLying.html
http://www.exrx.net/Stretches/Hamstrings/LyingSingleLeg.html

For a yoga approach:

http://www.yogajournal.com/poses/483
http://www.yogajournal.com/poses/2465
http://www.yogajournal.com/poses/863 (this is actually a rather lousy description of pigeon, but I can't find a better one without more coffee)